The synthesis of ribosomal proteins and their incorporation into mature ribosomes will be studied in the oocytes of Xenopus laevis. Attempts will be made to determine if some ribosomal proteins are synthesized as polycistronic polypeptides in these cells. Antibodies against ribosomal proteins and proteolytic inhibitors will be employed in this analysis. The steps in the assembly of ribosomes will be analyzed as well. Attempts will be made to isolate polysomes from X. laevis oocytes which contain the messenger RNAs for ribosomal proteins. If successful, a purification of these messenger RNAs for ribosomal proteins will then be attempted. The synthesis of mitochondrial DNA will also be investigated in X. laevis oocytes. The qualitative as well as quantitative aspects of this synthesis will be studied using incorporation of radioisotopes as well as electron microscopy. Particular attention will be paid to those stage oocytes which show the most rapid increase in mtDNA accumulation. Experiments will be performed to see if there is a parallel increase of mtDNA with other mitochondrial components in these growing oocytes.